[PATCH 5.10.y 4/7] arm64: dts: imx8mq-librem5: Set the DVS voltages lower

[Sasha Levin <sashal@kernel.org>]

From: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>

[ Upstream commit c24a9b698fb02cd0723fa8375abab07f94b97b10 ]

They're still in the operating range according to i.MX 8M Quad
datasheet. There's some headroom added over minimal values to
account for voltage drop.

Operational ranges (min - typ - max [selected]):
 - VDD_SOC (BUCK1): 0.81 - 0.9 - 0.99 [0.88]
 - VDD_ARM (BUCK2): 0.81 - 0.9 - 1.05 [0.84] (1000MHz)
                    0.90 - 1.0 - 1.05 [0.93] (1500MHz)
 - VDD_GPU (BUCK3): 0.81 - 0.9 - 1.05 [0.85] (800MHz)
                    0.90 - 1.0 - 1.05 [ -- ] (1000MHz)
 - VDD_VPU (BUCK4): 0.81 - 0.9 - 1.05 [ -- ] (550/500/588MHz)
                    0.90 - 1.0 - 1.05 [0.93] (660/600/800MHz)

Idle power consumption doesn't appear to be influenced much,
but a simple load test (`cat /dev/urandom | pigz - > /dev/null`
combined with running Animatch) seems to show about 0.3W of
difference.

Care is advised, as there may be differences between each
units in how low can they be undervolted - in my experience,
reaching that point usually makes the phone fail to boot.
In my case, it appears that my Birch phone can go down the most.

This is a somewhat conservative set of values that I've seen
working well on all my devices; I haven't tried very hard to
optimize it, so more experiments are welcome.

Signed-off-by: Sebastian Krzyszkowiak <sebastian.krzyszkowiak@puri.sm>
Signed-off-by: Martin Kepplinger <martin.kepplinger@puri.sm>
Signed-off-by: Shawn Guo <shawnguo@kernel.org>
Stable-dep-of: 511f76bf1dce ("arm64: dts: imx8mq-librem5: Bump BUCK1 suspend voltage up to 0.85V")
Signed-off-by: Sasha Levin <sashal@kernel.org>
---
 .../boot/dts/freescale/imx8mq-librem5-r3.dts  |  2 +-
 .../boot/dts/freescale/imx8mq-librem5.dtsi    | 22 ++++++++++++++-----
 2 files changed, 17 insertions(+), 7 deletions(-)

diff --git a/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts b/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts
index cd3c3edd48fa3..425f4ef7cb2dd 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts
+++ b/arch/arm64/boot/dts/freescale/imx8mq-librem5-r3.dts
@@ -12,7 +12,7 @@ / {
 
 &a53_opp_table {
 	opp-1000000000 {
-		opp-microvolt = <1000000>;
+		opp-microvolt = <950000>;
 	};
 };
 
diff --git a/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi b/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
index a299e4dfcce7e..39af36f789871 100644
--- a/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
+++ b/arch/arm64/boot/dts/freescale/imx8mq-librem5.dtsi
@@ -651,8 +651,8 @@ buck1_reg: BUCK1 {
 				regulator-max-microvolt = <1300000>;
 				regulator-boot-on;
 				regulator-ramp-delay = <1250>;
-				rohm,dvs-run-voltage = <900000>;
-				rohm,dvs-idle-voltage = <850000>;
+				rohm,dvs-run-voltage = <880000>;
+				rohm,dvs-idle-voltage = <820000>;
 				rohm,dvs-suspend-voltage = <800000>;
 				regulator-always-on;
 			};
@@ -663,8 +663,8 @@ buck2_reg: BUCK2 {
 				regulator-max-microvolt = <1300000>;
 				regulator-boot-on;
 				regulator-ramp-delay = <1250>;
-				rohm,dvs-run-voltage = <1000000>;
-				rohm,dvs-idle-voltage = <900000>;
+				rohm,dvs-run-voltage = <950000>;
+				rohm,dvs-idle-voltage = <850000>;
 				regulator-always-on;
 			};
 
@@ -673,14 +673,14 @@ buck3_reg: BUCK3 {
 				regulator-min-microvolt = <700000>;
 				regulator-max-microvolt = <1300000>;
 				regulator-boot-on;
-				rohm,dvs-run-voltage = <900000>;
+				rohm,dvs-run-voltage = <850000>;
 			};
 
 			buck4_reg: BUCK4 {
 				regulator-name = "buck4";
 				regulator-min-microvolt = <700000>;
 				regulator-max-microvolt = <1300000>;
-				rohm,dvs-run-voltage = <1000000>;
+				rohm,dvs-run-voltage = <930000>;
 			};
 
 			buck5_reg: BUCK5 {
@@ -1117,3 +1117,13 @@ &wdog1 {
 	fsl,ext-reset-output;
 	status = "okay";
 };
+
+&a53_opp_table {
+	opp-1000000000 {
+		opp-microvolt = <850000>;
+	};
+
+	opp-1500000000 {
+		opp-microvolt = <950000>;
+	};
+};
-- 
2.53.0